Hi Gary,

It's certainly a strange one...

I only hear it when something is plugged into the mic socket, even if it's only a 3.5mm to 6mm jack adaptor (the one I use in the headphone socket to shut the speakers off when listening through the hi-fi).

There are 4 ways for me to make the hiss and buzz disappear completely... either switch the noise gate on, mute the mic, or reduce the mic's volume slider considerably (all within the 'overall mic settings' tab).

The 4th way is to simply unplug the adaptor (or mic) from the mic socket.

As you say though, no one operates these keyboards at maximum levels (and the noise gate would generally be on) so I don't really mind that the hiss is audible at those levels... but it's interesting that yourself and others don't hear any.

Cheers,
Rich